Add a quick 'n dirty serializer for AST nodes

src/ast-spec.ts

@@ -4,6 +4,7 @@ import { TextSpan } from "./text"
 import { Value } from "./evaluator"
 import { Package } from "./package"
 import { Diagnostic } from "./diagnostics";
+import { serializeTag, serialize, JsonObject } from "./util";
 
 let nextNodeId = 1;
 
@@ -29,6 +30,17 @@ export abstract class Syntax {
     this.id = nextNodeId++;
   }
 
+  [serializeTag]() {
+    const result: JsonObject = {};
+    for (const key of Object.keys(this)) {
+      if (key === 'parentNode' || key === 'errors' || key === 'type' || key === 'id') {
+        continue;
+      }
+      result[key] = serialize((this as any)[key]);
+    }
+    return result;
+  }
+
   *preorder() {
     const stack: Syntax[] = [ this as unknown as Syntax ] ;
     while (stack.length > 0) {

src/ast.ts

@@ -8,6 +8,8 @@ import { Package } from "./package";
 
 import { Diagnostic } from "./diagnostics";
 
+import { serializeTag, serialize, JsonObject } from "./util";
+
 let nextNodeId = 1;
 
 export type ResolveSyntaxKind<K extends SyntaxKind> = Extract<Syntax, {
@@ -24,6 +26,16 @@ export abstract class SyntaxBase {
     constructor(public span: TextSpan | null = null) {
         this.id = nextNodeId++;
     }
+    [serializeTag]() {
+        const result: JsonObject = {};
+        for (const key of Object.keys(this)) {
+            if (key === 'parentNode' || key === 'errors' || key === 'type' || key === 'id') {
+                continue;
+            }
+            result[key] = serialize((this as any)[key]);
+        }
+        return result;
+    }
     *preorder() {
         const stack: Syntax[] = [this as unknown as Syntax];
         while (stack.length > 0) {